Semiconductor devices are commonly found in modern electronic products. Semiconductor devices vary in the number and density of electrical components. Discrete semiconductor devices generally contain one type of electrical component, e.g., light emitting diode (LED), small signal transistor, resistor, capacitor, inductor, and power metal oxide semiconductor field effect transistor (MOSFET). Integrated semiconductor devices typically contain hundreds to millions of electrical components. Examples of integrated semiconductor devices include microcontrollers, microprocessors, charged-coupled devices (CCDs), solar cells, and digital micro-mirror devices (DMDs).
Semiconductor devices perform a wide range of functions such as high-speed calculations, transmitting and receiving electromagnetic signals, controlling electronic devices, transforming sunlight to electricity, and creating visual projections for television displays. Semiconductor devices are found in the fields of entertainment, communications, power conversion, networks, computers, and consumer products. Semiconductor devices are also found in military applications, aviation, automotive, industrial controllers, and office equipment.
Semiconductor devices exploit the electrical properties of semiconductor materials. The atomic structure of semiconductor material allows its electrical conductivity to be manipulated by the application of an electric field or base current or through the process of doping. Doping introduces impurities into the semiconductor material to manipulate and control the conductivity of the semiconductor device.
A semiconductor device contains active and passive electrical structures. Active structures, including bipolar and field effect transistors, control the flow of electrical current. By varying levels of doping and application of an electric field or base current, the transistor either promotes or restricts the flow of electrical current. Passive structures, including resistors, capacitors, and inductors, create a relationship between voltage and current necessary to perform a variety of electrical functions. The passive and active structures are electrically connected to form circuits, which enable the semiconductor device to perform high-speed calculations and other useful functions.
Semiconductor devices are generally manufactured using two complex manufacturing processes, i.e., front-end manufacturing, and back-end manufacturing, each involving potentially hundreds of steps. Front-end manufacturing involves the formation of a plurality of die on the surface of a semiconductor wafer. Each die is typically identical and contains circuits formed by electrically connecting active and passive components. Back-end manufacturing involves singulating individual die from the finished wafer and packaging the die to provide structural support and environmental isolation.
One goal of semiconductor manufacturing is to produce smaller semiconductor devices. Smaller devices typically consume less power, have higher performance, and can be produced more efficiently. In addition, smaller semiconductor devices have a smaller footprint, which is desirable for smaller end products. A smaller die size may be achieved by improvements in the front-end process resulting in die with smaller, higher density active and passive components. Back-end processes may result in semiconductor device packages with a smaller footprint by improvements in electrical interconnection and packaging materials.
FIG. 1a shows a conventional semiconductor wafer 10 containing a base substrate material. A plurality of semiconductor die or components 12 is formed on wafer 10 separated by saw streets 14. A build-up interconnect structure 20 is formed over active surface 18 of semiconductor wafer 10. The build-up interconnect structure 20 includes a plurality of electrically conductive layers 22 separated by insulating or passivation layers 24. An insulating or passivation layer 28 is formed over build-up interconnect structure 20. A portion of insulating layer 28 is removed by an etching process to expose conductive layers 22 and saw street 14. A plurality of bumps 26 is formed over the exposed conductive layers 22. A lamination tape 30 is applied over the top surface of semiconductor wafer 10, i.e., insulating layer 28 and bumps 26, to provide structural support for the wafer during subsequent manufacturing processes. When lamination tape 30 is removed, a tape residue 34 is often left behind over insulating layer 28, particularly between bumps 26, as shown in FIG. 1b. FIG. 1c shows a top view of a portion of semiconductor wafer 10 with tape residue 34 remaining over insulating layer 28 and between bumps 26 after removal of lamination tape 30. Tape residue 34 reduces topside wafer quality and increases defects during inspection.